Apparatus for steeping cellulose



Nov. 5, 1940. w. GRC'DTZINGER 2,220,600

I APPARATUS FOR STEEPING CELLULOSE Filed April 7, 1959 g l l NVENTOR. Mil-M244 6P 727N652 ATTORNEY I Patented Nov. 5, 1940 UNITED STATES APPARATUS FOR STEEPING CELLULOSE Wilhelm Griitzinger, Stuttgart-Bad Cannstatt, Germany, assignor to Baker Perkins Company, Inc., Saginaw, Mich., a corporation of New York Application April '7, 1939, Serial No. 266,495

1 Claim.

This invention relates to apparatus for treating cellulose or like materials in caustic solution or other Iiquid, as described in my copending United States Patent, No. 2,174,241, issued Sep- 5 tember 26, 1939; and has for its object the provision of novel apparatus for collecting the treating solution pressed from the treated material, separating the first pressed dirty solution from the cleaner solution subsequently extracted from the material, directing it to waste and directing the cleaner solution back to the treating vat or tank for reuse.

The invention by which this'object is attained utilizes in a novel manner certain properties of cellulose or like fibrous or finely divided material when pressed in a mass. Before pressing a batch of cellulose the dirt originally in the cellulose which renders the solution unfit for further use is distributed throughout the mass, while any dirt present in the bath will be additionally deposited in the margina1 surfaces of the mass as the solution penetrates toward its center. When pressure is first applied the dirt suspended in the fluid around the margins of the mass of material is carried out with the liquid, which is thereby soiled. As further pressure is applied liquid is forced out from the central portion of the mass and is filtered through a substantial depth of fibrous material. Thus when this liquid reaches the surface of the mass it is substantially cleaner than that first extracted and is usable for further treatment of additional cellulose.

The invention, which takes advantage of this characteristic of the treated material, consists of the provision of a two-way valve and duct system between the funnel or pan which collects the extracted liquid, the treating vat and a waste tank or sewer. One duct leads from the valve to the vat, the other leads to waste; and the valve is operatively connected to or otherwise actuated synchronously with the drive or control mechanism of the pressure means so that during the first part of the pressing operation the liquid expressed is directed to waste, then during the remainder of the pressing operation the remainder of the liquid is returned to the treating vat for further use.

One embodiment of the invention is illus- 5 trated diagrammatically in the accompanying drawing in which like numerals designate like parts throughout the same. Reference may be had also to Figs. 1, 2, and '7 of the drawing of my copending patent referred to above, in which 55 corresponding elements are similarly numbered and which show such elements in their relation to a complete treating apparatus.

Referring to the drawing,

Fig. 1 is a diagrammatic side elevation of one end of a continuous treating apparatus, showing 5 the invention in its relation thereto. A hydraulic ram and the synchronously actuated valve are shown in their positions in which expressed liquid is sent to waste during the first v part of an extracting operation; and

Fig. 2 is a part sectional view of the apparatus of Fig. 1, showing the ram and the valve at the end of an extracting operation, with the expressed liquid being returned to the treating vat. 1i;

Figs. 1 and 2 show containers I carrying sheets of felted cellulose pivotally suspended at intervals from a pair of conveyor chains 2. The conveyor chains 2 pass around a series of sprockets in a circuitous path (shown fully in the parent {20 application), including sprockets 9 and I0 shown in'Fig. 1. Conveyor chains 2 are driven as described in said copending application or by other suitable means, with an intermittent step-bystep motion. The containers I travel from ag25 loading station to a treating vat l5, through which they are carried in close order 'upon a second conveyor 35 traveling around sprockets, as shown at 31. During its passage through treating vat IS, the cellulose in the containers is 30 treated for the requisite length of time, after which the containers are lifted from vat l5 by chains 2, as shown in Fig. 1. As they travel up.- wardly each container comes to rest between the anvil l1 and pallet I8 of a press of suitable con- 35 struction, shown diagrammatically here and in my original application as hydraulically actuated. The press, l1, I8 is coupled to the drive mechanism of conveyor 2 so that it is put into operation each time the conveyor comes to rest. 40 The excess treating solution is pressed from the cellulose and disposed of by the novel apparatus of the invention, as described below.

The operation of conveyor 2 and the synchronously governed press l1, l8 follows the follow- 45 ing cycle:

As each container reaches the press the conveyor 2 stops and the pallet l8 travels to the right, pressing the contents of the container against the anvil I1. At the conclusion of its stroke the pallet l8 moves back out of engagement with the container and the conveyor 2 moves another pitch distance, bringing the next container into position for pressing.

Beneath the press a drip pan or funnel 40 is positioned to receive and drain away the excess solution pressed from the cellulose in containers I. In the apparatus shown, the funnel is pivoted to permit it to swing free of containers I on the conveyor as they pass. This feature, however, forms no part of the present invention, which is applicable also to a batch pressing plant in which the masses of cellulose are placed in the press manually or by means other than a conveyor. The outlet 43 of funnel 40 is positioned at all times over a stationary funnel44, which in turn drains into a two-way valve 45. Valve 45 has two alternative outlets, 46 and 41. Outlet 46 leads to waste and outlet 41 is connected by a duct, not shown, toreturn liquid to vat l5. Through it the so-calledyellow caustic solution which is pressed from the cellulose and is still usable for treating purposes is returned to the vat. Outlet 46 is connected to a waste tank where the black caustic solution is collected, or a sewer.

The valve 45 is operatively-coupled by suitable known means to some part of the conveyor mechanism or directly to the'press itself. Inthe embodiment illustrated the valve is provided with a lever arm 48 connected by alever 49 pivoted at 5!) to some part of the frame (not shown).

The upper end of lever "49 is pivotally secured to a rod 5| fixed to'the'pallet lBof the press.

Dur'mg each pressing operationthe pallet I8 moves to the right into the-position shown in Fig. 1, and through the connecting links 48- 5l the valve '45 is positioned to direct fluid to waste outlet '46. As the press moves further to the right toward the position shown in Fig. 2 the valve is rotated into the position: shown in Fig. 2,

so that it directs fluid through outlet41-back to the vat l5. The point at which the valve is turned from one positiontothe other is determined by observation of the stage in the pressing operation at which the fluid extracted becomes sufiiciently clean for reuse. The timing of valve 45 may be adjusted during the consumption of a vat full of fluid by suitable means not shown, so that as the fluid becomes dirtier through continuous use the proportion returned to the vat is reduced, that is, the valve will turn later in the pressing stroke.

By thus automatically discarding the solution first pressed from the cellulose and returning the cleaner solution subsequently extracted to vat I5, a considerable saving in solution is effected. Only enough fresh caustic solution need be added to the vat to replace the dirty solution discharged through outlet 46. The improved apparatus thus automatically skims ofi the spent solution.

Various changes and modifications in individual elements of the apparatus described may be made without departing from the invention and the scope of the claim. Also, certain novel elementsmay be used by themselves or with other apparatus. For example, the two-way valve assembly, operatively associated with the press, may be employed profitably in the earlier used apparatus above referred to for extracting caustic solution from individual batches of cellulose. It is also applicable to other filter presses for the removal of solvents or other liquids from treated materials, wherein the first liquid pressed from the outside of a mass of material is more dirtladen than that later extracted from the inside of the mass-and filtered through the outer portions.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

In combination witha bath for treating batches of fibrous or otherporous material and pressure means for extractingfrom said material excess solution in which it has been treated, a funnel for receiving the solution so extracted, a two- 

